Methods and apparatus for enhancing selectivity of titanium and titanium silicides during chemical vapor deposition

ABSTRACT

Methods and apparatus for selectively depositing a titanium material layer atop a substrate having a silicon surface and a dielectric surface are disclosed. In embodiments an apparatus is configured for forming a remote plasma reaction between titanium tetrachloride (TiCl4), hydrogen (H2) and argon (Ar) in a region between a lid heater and a showerhead of a process chamber at a first temperature of 200 to 800 degrees Celsius; and flowing reaction products into the process chamber to selectively form a titanium material layer upon the silicon surface of the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional patent applicationSer. No. 62/785,999, filed Dec. 28, 2018, which is herein incorporatedby reference in its entirety.

FIELD

Embodiments of the present disclosure generally relate to substrateprocessing equipment and techniques, and more particularly, to methodsand apparatus for selectively depositing materials via chemical vapordeposition.

BACKGROUND

Selective deposition processes can advantageously reduce the number ofsteps and cost involved in conventional lithography while keeping upwith the pace of device dimension shrinkage. Selective deposition in atitanium and/or titanium silicide dielectric pattern is of highpotential value as titanium and titanium silicide (TiSix) is animportant material widely used to form ohmic contacts and reduce contactresistance of transistors connections. The inventors have observed poorselectivity of titanium materials between silicon and dielectrics suchas silicon nitride and silicon oxide raise a severe challenge inmaximizing metallic feature fill, e.g., poor selectivity may result intitanium material deposition on the sidewalls and bottom of a highaspect ratio feature and limit the ability to fill the feature with adesired metallic material. Because poor selectivity may promotenon-uniformity of the substrate, highly selective deposition of titaniummaterial towards silicon is needed to reduce contact resistance andmaximize volume of feature fill material.

Accordingly, the inventors have developed improved methods for selectivedeposition of titanium materials towards silicon or an exposed silicon,and away from dielectrics such as silicon oxide and silicon nitride.

SUMMARY

Methods and apparatus for selective deposition are provided herein. Insome embodiments, a method of selectively depositing a titanium materiallayer atop a substrate having a silicon surface and a dielectricsurface, includes: forming a remote plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) in a region betweena lid heater and a showerhead of a process chamber at a firsttemperature of 200 to 800 degrees Celsius; and flowing reaction productsinto the process chamber to selectively form a titanium material layerupon the silicon surface of the substrate.

In some embodiments, a method of selectively depositing a titaniummaterial layer atop a substrate having a silicon surface and adielectric surface, includes: forming a remote plasma reaction betweentitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) within aprocess chamber between a lid heater and a showerhead to form a titaniummaterial layer upon a substrate inside the process chamber toselectively deposit the titanium material layer atop the silicon surfaceof the substrate, wherein the dielectric surface inhibits deposition ofthe titanium material layer atop the dielectric surface, and wherein theremote plasma reaction reacts titanium tetrachloride (TiCl₄), hydrogen(H₂) and argon (Ar) at a first temperature of 200 to 800 degreesCelsius.

In some embodiments, a method of depositing a titanium material layeratop a substrate having a silicon surface and a dielectric surface,includes: optionally, forming a first direct plasma reaction betweentitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) inside aprocess chamber between a showerhead and a substrate for a duration of0.1 to 200 seconds; forming a remote plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) within a processchamber between a lid heater and a showerhead to form a titaniummaterial layer upon a substrate inside a processing chamber toselectively deposit the titanium material layer atop the silicon surfaceof the substrate, wherein the dielectric surface inhibits deposition ofthe titanium material layer atop the dielectric surface, and wherein theremote plasma reaction reacts titanium tetrachloride (TiCl₄), hydrogen(H₂) and argon (Ar) at a first temperature of 200 to 800 degrees Celsiusto pass titanium material through the showerhead; and forming a directplasma reaction between nitrogen (N₂), hydrogen (H₂) and argon (Ar)inside a process chamber between the showerhead and the substrate toform a capping titanium nitride layer for the titanium material layeratop the silicon surface of the substrate.

In some embodiments, the present disclosure relates to a processingchamber, comprising: a lid heater; a showerhead, and a substrate supportpositioned within the processing chamber, wherein the processing chamberis configured to remotely ignite a plasma in a region between the lidheater and the showerhead and directly ignite a plasma between theshowerhead and the substrate support.

In some embodiments, the present disclosure relates to a processingchamber including a lid heater, a showerhead, and a substrate supportpositioned within the processing chamber, wherein the processing chamberis configured to remotely ignite a plasma inside a process chamberbetween a lid heater and a showerhead and directly ignite a plasmabetween the showerhead and the substrate support.

In some embodiments, the present disclosure relates to a non-transitorycomputer readable medium having instructions stored thereon that, whenexecuted, cause a method of selectively depositing a titanium materiallayer atop a substrate having a silicon surface and a dielectricsurface, including: forming a remote plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) in a region betweena lid heater and a showerhead of a process chamber at a firsttemperature of 200 to 800 degrees Celsius; and flowing reaction productsinto the process chamber to selectively form a titanium material layerupon the silicon surface of the substrate.

Other and further embodiments of the present disclosure are describedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure, briefly summarized above anddiscussed in greater detail below, can be understood by reference to theillustrative embodiments of the disclosure depicted in the appendeddrawings. However, the appended drawings illustrate only typicalembodiments of the disclosure and are therefore not to be consideredlimiting of scope, for the disclosure may admit to other equallyeffective embodiments.

FIG. 1 is a schematic illustration of an apparatus suitable forpracticing the methods of the present disclosure;

FIG. 2 is a flowchart of a method of selective deposition in accordancewith some embodiments of the present disclosure;

FIGS. 3A-3B are illustrative cross-sectional views of the substrateduring different stages of the processing sequence of FIG. 2 inaccordance with some embodiments of the present disclosure;

FIG. 4 is a flow diagram of a method of selective deposition inaccordance with some embodiments of the present disclosure; and

FIGS. 5A-5C are illustrative cross-sectional views of the substrateduring different stages of the processing sequence of FIG. 4 inaccordance with some embodiments of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. The figures are not drawn to scale and may be simplifiedfor clarity. Elements and features of one embodiment may be beneficiallyincorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

Methods and apparatus for selective deposition are provided herein. Insome embodiments, a method of selectively depositing a titanium materiallayer atop a substrate having a silicon surface and a dielectricsurface, includes: forming a remote plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) in a region betweena lid heater and a showerhead of a process chamber at a firsttemperature of 200 to 800 degrees Celsius; and flowing reaction productsinto the process chamber to selectively form a titanium material layerupon the silicon surface of the substrate. In some embodiments, themethods described herein advantageously enhance and promote selectivityof titanium materials towards silicon and decrease selectivity towardsdielectrics such as silicon nitride and silicon oxide. The methodsfacilitate and promote maximizing metallic feature fill, e.g.,increasing selectivity towards the bottom of a feature including siliconand reducing titanium material deposition on the sidewalls of a highaspect ratio feature including a dielectric to increase the volumewithin a feature to be filled with a desired metallic material. Becausethe high selectivity towards silicon promotes uniformity of thesubstrate, contact resistance is advantageously reduced and the volumeof feature fill material is advantageously maximized. In someembodiments, the showerhead traps reaction products such as titaniummaterial ions within the showerhead to facilitate selective deposition.In some embodiments, a pretreatment including heating the substrate inthe presence of silane further enhances selectivity towards silicon, andaway from silicon nitride. In some embodiments, such as where thetitanium material is titanium, pretreatment enhances selectivity towardssilicon to greater than 40:1. In some embodiments, such as where thetitanium material is titanium silicide, pretreatment enhancesselectivity towards silicon to greater than 60:1. In some embodiments, apost-deposition treatment including contacting the showerhead andsubstrate with silane and/or remote plasma hydrogen such as hydrogenradicals may reduce memory effect, where titanium nitride deposits filmatop the substrate on both silicon and silicon nitride (SiN) to lessthan 3 angstroms and further enhances selectivity towards silicon, andaway from silicon nitride.

FIG. 1 is a schematic illustration of an apparatus such as waferprocessing system 10 suitable for practicing the methods of the presentdisclosure. In embodiments, the wafer processing system 10 includes aprocess chamber 100, a gas panel 130, a control unit 110, along withother hardware components such as power supplies and vacuum pumps.Exemplary process chambers may include any of several process chambersconfigured for remote and direct chemical vapor deposition (CVD)reactions as described herein, available from Applied Materials, Inc. ofSanta Clara, Calif. Other suitable process chambers from othermanufacturers may similarly be used and modified in accordance with thepresent disclosure.

In embodiments, the process chamber 100 generally comprises a lid heater131, which is used to heat processing volume 101 including a region suchas a plenum space between lid heater 131 and showerhead 165 within theprocess chamber 100. Depending on the specific process, processingvolume 101 in a region between lid heater 131 and showerhead 165 may beheated to some desired temperature prior to and during processing inaccordance with the present disclosure. In embodiments, the lid heater131 is heated by an embedded heating element such as heating element171. For example, lid heater 131 may be resistively heated by applyingan electric current from an AC supply (not shown) to the heating element171. The processing volume 101 region between lid heater 131 andshowerhead 165 is, in turn, heated by the lid heater 131, and can bemaintained within a process temperature range of, for example, 200 to800 degrees Celsius, or at a first temperature of about 550 degreesCelsius. In some embodiments, the region between a lid heater and ashowerhead of a process chamber is maintained at a first temperature of200 to 800 degrees Celsius. In some embodiments, providing a lid heaterat a temperature of 200 to 800 degrees Celsius or in some embodimentsabout 550 degrees Celsius, a showerhead at about 500 degrees Celsius(heated by radiant heat from the lid heater), a wafer temperature ofabout 425 degrees Celsius, and a pedestal heated to about 450 degreesCelsius may heat the region between the lid heater and the showerhead toa temperature of 200 to 800 degrees Celsius or in some embodiments,about 550 degrees Celsius. In embodiments, the region between the lidheater and the showerhead is characterized as a plenum space.

In embodiments, a temperature sensor (not shown), such as athermocouple, may be embedded in the lid heater 131 to monitor thetemperature of the lid heater 131 in a conventional manner. For example,the measured temperature may be used in a feedback loop to control thepower supply for the lid heater 131 such that the processing volume 101temperature of a region between lid heater 131 and showerhead 165 can bemaintained or controlled at a desired temperature that is suitable forthe particular process application. In embodiments, the lid heater 131is configured to provide heat sufficient to promote remote plasmaformation in processing volume 101 between lid heater 131 and showerhead165, or within showerhead 165 and prevent condensation within or uponshowerhead 165. For example, control unit 110 may be in communicationwith the lid heater 131 so that a user can adjust the heat of lid heater131 and maintain a heat sufficient for remote plasma formation. Inembodiments, depending upon processing needs, lid heater 131 isconfigured not to heat, or promote remote plasma formation in processingvolume 101 in a region between lid heater 131 and showerhead 165. Forexample, the lid heater 131 may be switched off by way of control unit110 depending upon user needs.

In embodiments, a radio frequency electrode 181 may be embedded in thelid heater 131 to configure the lid heater 131 for providing radiofrequency in an amount sufficient to form a plasma adjacent the lidheater 131. In embodiments, the lid heater 131 is configured to provideRF sufficient to promote remote plasma formation in processing volume101 in a region between lid heater 131 and showerhead 165, and/or withinshowerhead 165. For example, control unit 110 may be in communicationwith the lid heater 131 so that a user can adjust the RF emitted fromlid heater 131 and maintain RF signal sufficient for plasma formation.In embodiments, depending upon processing needs, lid heater 131 isconfigured not to emit RF signal or promote plasma formation inprocessing volume 101 between lid heater 131 and showerhead 165. Forexample, the lid heater 131 may be switched off by way of control unit110 depending upon user needs eliminating RF generated therefrom.

In embodiments, the process chamber 100 generally includes a supportpedestal 150, which is used to support a substrate such as asemiconductor substrate 190 within the process chamber 100. The supportpedestal 150 can be moved in a vertical direction inside the processchamber 100 using a displacement mechanism (not shown). Depending on thespecific process, semiconductor substrate 190 may be heated to somedesired temperature prior to processing. In embodiments, the supportpedestal 150 is heated by an embedded heating element such as heatingelement 170. For example, the support pedestal 150 may be resistivelyheated by applying an electric current from an AC supply 106 to theheating element 170. The semiconductor substrate 190 is, in turn, heatedby the support pedestal 150, and can be maintained within a processtemperature range of, for example, 200 to 800 degrees Celsius or 300 to700 degrees Celsius. In embodiments, a temperature sensor 172, such as athermocouple, may be embedded in the support pedestal 150 to monitor thetemperature of the support pedestal 150 in a conventional manner. Forexample, the measured temperature may be used in a feedback loop tocontrol the power supply such as AC supply 106 for the heating element170 such that the semiconductor substrate 190 temperature can bemaintained or controlled at a desired temperature that is suitable forthe particular process application. In embodiments, the support pedestalincludes a ground at 182.

In embodiments, proper control and regulation of gas flows through theprocess chamber 100 and gas panel 130 is performed by mass flowcontrollers (not shown) and a controller unit 110 such as a computer.The showerhead 165 allows process gases from the gas panel 130 to beuniformly distributed and introduced into the process chamber 100. Inembodiments, showerhead 165 is configured for flowing reaction products(such as reaction products suitable for forming a titanium materiallayer such as titanium or titanium silicide as described herein) intothe process chamber to selectively form a titanium material layer uponthe silicon surface of the substrate.

Illustratively, the control unit 110 includes a central processing unit(CPU) 112, support circuitry 114, and memories containing associatedcontrol software 116. The control unit 110 is responsible for automatedcontrol of the numerous steps required for semiconductor substrate 190processing such as wafer transport, gas flow control, temperaturecontrol, chamber evacuation, and so on. Bi-directional communicationsbetween the control unit 110 and the various components of the waferprocessing system 10 are handled through numerous signal cablescollectively referred to as signal buses 118, some of which areillustrated in FIG. 1.

In some embodiments, the present disclosure relates to a non-transitorycomputer readable medium, such as memory, having instructions storedthereon that, when executed, cause a method of selectively depositing atitanium material layer atop a substrate having a silicon surface and adielectric surface, including: forming a remote plasma reaction betweentitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) in a regionbetween a lid heater and a showerhead of a process chamber at a firsttemperature of 200 to 800 degrees Celsius; and flowing reaction productsinto the process chamber to selectively form a titanium material layerupon the silicon surface of the substrate.

In some embodiments, a radio frequency electrode 181 may be embedded inthe showerhead 165 to configure the showerhead 165 for providing RFenergy in an amount sufficient to form a plasma adjacent the showerhead165. In embodiments, the showerhead 165 is configured to provide RFsufficient to promote plasma formation in processing volume 101. Forexample, control unit 110 may be in communication with the showerhead165 so that a user can adjust RF emitted from showerhead 165 andmaintain RF signal sufficient for plasma formation. In embodiments, theshowerhead 165 may optionally be grounded by ground 183 depending uponuser needs for plasma placement within processing volume 101. Inembodiments, wherein showerhead 165 is grounded, a remote plasma mayform in a region between lid heater 131 and showerhead 165 in processingvolume 101. In embodiments, wherein showerhead is not grounded, a directplasma is formed in a region between the showerhead 165 andsemiconductor substrate 190 in processing volume 101. A switch 184 maybe in communication with the ground 183 and RF electrode 180 andshowerhead and configured to control remote and direct plasma formationin accordance with the present disclosure and depending upon user needs.In embodiments the switch 184 and showerhead 165 are in communicationand configured to control remote and direct plasma formation inaccordance with the present disclosure and depending upon user needs. Insome embodiments, a power supply such as an RF or VHF power supply, iselectrically coupled to the chamber lid via a switch 184 when the switchis disposed in a first position. When the switch is disposed in a secondposition (not shown) the power supply is electrically coupled to theshowerhead 165. When the switch 184 is in the first position, the powersupply is used to ignite and maintain a first plasma which is remotefrom the substrate, such as a remote plasma disposed in the plenum spaceor region directly between the lid heater and showerhead. In someembodiments, a remote plasma is composed of the processing gases flowedinto the plenum and maintained as a plasma by capacitive coupling ofpower from the power supply. In some embodiments, when the switch 184 isin a second position, the power supply is used to ignite and maintain asecond plasma (not shown) in the processing volume 101 between theshowerhead 165 and the substrate 190 disposed on the substrate support.

In embodiments, process chamber 100 includes a vacuum pump 102 toevacuate the process chamber 100 and to maintain the proper gas flowsand pressure inside the process chamber 100. A showerhead 165, throughwhich process gases are introduced into the process chamber 100, islocated above the support pedestal 150. In embodiments, showerhead 165may be configured as a multiple gas showerhead having two or moreseparate pathways, which allow two or more gases to be separatelyintroduced into the processing chamber 100 without premixing. In someembodiments, showerhead 165 is connected to a gas panel 130 whichcontrols and supplies, through mass flow controllers (not shown),various gases used in different steps of the process sequence. Duringwafer processing, a purge gas supply 104 also provides a purge gas, forexample, an inert gas, around the bottom of the support pedestal 150 tominimize undesirable deposits from forming on the support pedestal 150.

In embodiments, control unit 110 is responsible for controlling gas flowfrom gas panel 130 to the processing volume 101 such as a region betweenlid heater 131 and showerhead 165 by a first gas flow line 162, orwithin showerhead 165 by a second gas flow line 163. In someembodiments, process chamber 100 is configured such that gas panel 130provides titanium tetrachloride (TiCl₄), hydrogen (H₂) and/or argon (Ar)or a noble gas inside process chamber 100 and processing volume 101. Forexample, in embodiments, processing volume 101 is configured to receivetitanium tetrachloride (TiCl₄) at about 1 to 100 sccm or about 25 sccm.In embodiments, processing volume 101 is configured to receive hydrogen(H₂) at about 50 to 10000 sccm, or about 500 sccm. In embodiments,processing volume 101 is configured to receive about 3.5 liters ofargon. In some embodiments, one or more desired gases may be directedfrom gas panel 130 into processing volume 101 via a second gas flow line163. For example, in embodiments, silane such as SiH₄, disilane such asSi₂H₆, silane compound, or hydrogen (H2), or noble gas such as argon(Ar) gases may be added to processing volume 101 by second gas flow line163. In some embodiments, such as where processing chamber 100 isconfigured for remote plasma application, e.g., igniting plasma in aregion between lid heater 131 and showerhead 165, or within showerhead165, one or more desired gases such as titanium tetrachloride (TiCl₄),hydrogen (H₂) and/or argon (Ar) may be directed from gas panel 130 intoprocessing volume 101 via a first gas flow line 162, and one or moredesired gases such as silane such as SiH₄, or hydrogen (H2), or argon(Ar) gases may be directed to processing volume 101 by second gas flowline 163. In some embodiments, the inclusion of silane during depositionof titanium material results in the formation of titanium silicide orTiSix. In some embodiments TiSix refers to titanium silicide, wherein xis a number between 0.4 and 2.2. In some embodiments, TiSix refers toone or more of Ti₅Si₃, TiSi₂, TiSi, or combinations thereof.

In embodiments, the flow rate, temperature, and pressure of theprocessing volume can be adjusted to a value sufficient for a reactiondesired in accordance with the present disclosure. In some embodiments,such as where processing chamber 100 is configured for direct plasmaapplication, e.g., igniting plasma in a region between showerhead 165and semiconductor substrate 190, one or more desired gases such asnitrogen (N₂), hydrogen (H₂) and argon (Ar) may be directed from gaspanel 130 into processing volume 101 via a first gas flow line 162, andone or more desired gases such as argon (Ar) may be directed toprocessing volume 101 by second gas flow line 163. In embodiments, theflow rate, temperature, and pressure of the processing volume can beadjusted to a value sufficient for a reaction desired in accordance withthe present disclosure.

In embodiments, processing chamber 100 includes an RF electrode 180sufficient for igniting plasma within the process volume 101 inaccordance with the present disclosure. In embodiments, the RF electrode180 may be coupled to one or more power sources (one power source notshown) through one or more respective matching networks (matchingnetwork shown). The one or more power sources may be capable ofproducing up to 3000 watts of RF energy at a frequency of about 350 kHzto about 60 MHz, such as at about 350 kHz, or about 13.56 MHz, or about60 Mhz. In embodiments, about 65 watts to 150 watts of RF energy isapplied to the remote plasma reaction within process volume 101. In someembodiments, RF energy is about 120 watts to 140 watts or 130 aboutwatts. In some embodiments, pulsed RF energy or RF in a continuous wavemode is applied. In some embodiments, the RF power is about 130 watts,with a pulsed frequency of about 1 kHz, and a duty cycle about 50%. Insome embodiments, processing chamber 100 may utilize capacitivelycoupled RF energy for plasma processing. For example, the processchamber 100 may have a ceiling made from dielectric materials and ashowerhead 165 that is at least partially conductive to provide an RFelectrode (or a separate RF electrode may be provided). The showerhead165 (or other RF electrode) may be coupled to one or more RF powersources (one RF power source not shown) through one or more respectivematching networks (matching network not shown). The one or more plasmasources may be capable of producing up to about 3,000 watts, or in someembodiments, up to about 5,000 watts, of RF energy.

FIG. 2 is a flowchart of a method 200 of selective deposition inaccordance with some embodiments of the present disclosure. FIGS. 3A-3Bare illustrative cross-sectional views of the substrate such assemiconductor substrate 190 during different stages of the processingsequence of FIG. 2 in accordance with some embodiments of the presentdisclosure. The methods of the present disclosure may be performed inprocess chambers configured for thermal deposition techniques such aschemical vapor deposition (CVD), or the process chamber discussed abovewith respect to FIG. 1.

In embodiments, the method 200 is performed on a semiconductor substrate190, as depicted in FIG. 3A, having a silicon surface 302 extendingacross the bottom of feature 351 and one or more dielectric surfacessuch as dielectric surface 304. In embodiments, semiconductor substrate190 may comprise a silicon material 301 such as crystalline silicon(e.g., Si<100> or Si<111>), silicon germanium, doped or undopedpolysilicon, doped or undoped silicon wafers, patterned or non-patternedwafers, silicon on insulator (SOI), and combinations thereof. Inembodiments, semiconductor a silicon material 301 may comprise orconsist of a material such as crystalline silicon (e.g., Si<100> orSi<111>), pure silicon, substantially pure silicon (having less than 1%,or less than 0.5% impurities), or exposed silicon, such as a pretreatedsilicon with a native oxide layer removed. In embodiments, thesemiconductor substrate 190 may have various dimensions, such as 200 mm,300 mm, 450 mm or other diameters for round substrates. Thesemiconductor substrate 190 may also be any polygonal, square,rectangular, curved or otherwise non-circular workpiece, such as apolygonal glass substrate used in the fabrication of flat paneldisplays. Unless otherwise noted, implementations and examples describedherein are conducted on substrates such as semiconductor substrate 190with, for example, a 200 mm diameter, a 300 mm diameter, or a 450 mmdiameter substrate.

In some embodiments, silicon material 301 is deposited via any suitableatomic layer deposition process or a chemical layer deposition process.In some embodiments, the silicon material 301 may comprise any suitablesilicon material for semiconductor device fabrication. Referring to FIG.3A, a silicon oxide layer (not shown) may be atop silicon surface 302.The silicon oxide layer may be a native oxide layer or form as siliconsurface 302 contacts oxygen, for example in air or water. In someembodiments, silicon oxide layer may be problematic in that the siliconoxide layer may be less selective towards titanium materials than anexposed silicon surface. In some embodiments, method 200 may include,pre-treating the silicon surface 302 to form an exposed silicon surface.In some embodiments, methods include contacting the silicon surface 302with one or more etchants to form an exposed silicon surface 302. Insome embodiments, a silicon oxide layer is removed prior to depositing atitanium material atop, or directly atop silicon surface 302 to form anexposed silicon surface. Non-limiting examples of exposed siliconsurface material includes substantially pure, for example, substantiallyfree of oxide, silicon and the like.

In embodiments, dielectric layer 305 including dielectric surface 304 isnot the same as silicon material 301 including silicon surface 302. Insome embodiments, the dielectric layer 305 is deposited via any suitableatomic layer deposition process or a chemical layer deposition process.In some embodiments, the dielectric layer 305 may comprise a low-kdielectric layer deposited atop silicon material 301. In someembodiments, dielectric layer 305 may include any low-k dielectricmaterial suitable for semiconductor device fabrication, and combinationsthereof. Non-limiting materials suitable as low-k dielectric materialmay comprise a silicon containing material, for example, such as siliconoxide (SiO2), silicon nitride, or silicon oxynitride (SiON), orcombinations thereof, or combinations of layers thereof. In embodiments,the low-k dielectric material may have a low-k value of less than about3.9 (for example, about 2.5 to about 3.5). In some embodiments, thedielectric layer 305 may comprise hafnium oxide such as HfO_(x). Inembodiments, dielectric layer 305 and dielectric surface 304 comprise orconsist of silicon oxide (SiO₂), silicon nitride, silicon oxynitride(SiON), or combinations thereof.

In some embodiments, the substrate is optionally pretreated as shown inprocess sequence 201 of method 200. In some embodiments, the dielectriclayer 305 is pretreated by contacting the dielectric layer 305 withsilane alone or in combination with a noble gas such as argon. In someembodiments, dielectric layer 305 comprises a nitrogen material such assilicon nitride, and the substrate may be preheated prior to depositinga titanium material layer. In some embodiments, during a method ofselectively depositing a titanium material layer atop a substrate havinga silicon surface and a dielectric surface, such as silicon nitride,prior to forming a remote plasma reaction between titanium tetrachloride(TiCl₄), hydrogen (H₂) and argon (Ar) in a region between a lid heaterand a showerhead of a process chamber at a first temperature of 200 to800 degrees Celsius, the substrate is preheated to a temperature of 200to 800 degrees Celsius by contacting the substrate and dielectricsurface with heated gas such as heated argon or hydrogen. Referring toFIG. 1, in some embodiments, argon and hydrogen may be flowed via firstgas flow line 162 and heated to preheat the substrate. In someembodiments, silane and argon may be flowed through second gas flow line163 while preheating the substrate. In embodiments, about 500 sccm to3000 sccm of silane is flowed through second gas flow line 163 to reactwith and/or cover dielectric surface 304. In some embodiments, thedielectric surface is silicon nitride (SiN) and silane is contacted withthe dielectric surface in an amount sufficient to saturate an exposedsurface of the dielectric surface 304. In embodiments, silane bonds tothe silicon in a silicon nitride layer of dielectric surface 304,further enhancing selectivity of titanium material towards silicon. Insome embodiments, a pretreatment including heating the substrate in thepresence of silane further enhances selectivity towards silicon, andaway from silicon nitride. In some embodiments, such as where thetitanium material is titanium, pretreatment enhances selectivity towardssilicon to greater than 40:1 such as 45:1. In some embodiments, such aswhere the titanium material is titanium silicide, pretreatment enhancesselectivity towards silicon to greater than 60:1 such as 68:1.

In some embodiments, the method 200 optionally begins at 201 bypretreating a substrate such as by preheating as described above to atemperature above 200 degrees Celsius or between 200 degrees Celsius to800 degrees Celsius. In some embodiments, such as where the dielectricsurface is silicon nitride, the substrate may be further contacted withsilane during pretreatment as described above.

In some embodiments, the present disclosure relates to a method ofselectively depositing a titanium material layer atop a substrate havinga silicon surface and a dielectric surface including silicon nitride,including: preheating the substrate by contacting the substrate withhydrogen and argon at a temperature above room temperature (such as atemperature of 200 to 800 degrees Celsius) while contacting thesubstrate with argon and silane; subsequently forming a remote plasmareaction between titanium tetrachloride (TiCl₄), hydrogen (H₂) and argon(Ar) in a region between a lid heater and a showerhead of a processchamber at a first temperature of 200 to 800 degrees Celsius; andflowing reaction products into the process chamber to selectively form atitanium material layer upon the silicon surface of the substrate. Insome embodiments, silane and argon are supplied through second gas flowline 163 to form a titanium material layer comprising or consisting oftitanium silicide (TiSix). In embodiments, a silane (SiH₄) pre-soakenhances selectivity for remote plasma chemical vapor deposition (CVD)titanium and remote plasma CVD titanium silicide (TiSix) depositionprocess. In embodiments, pretreated as shown in process sequence 201includes preheating the substrate by contacting the substrate withhydrogen and argon at a temperature above room temperature (such as atemperature of 200 to 800 degrees Celsius) while contacting thesubstrate with argon and silane.

In embodiments, the dielectric layer 305 may include one or morefeatures 351 such as a via or trench formed in the dielectric layer 305.The one or more features 351 may be formed by etching the dielectriclayer 305 using any suitable etch process. In some embodiments, the oneor more features 351 is defined by one or more sidewalls 314, an opening322 and upper corners 321. In some embodiments, the one or more features351 may have a high aspect ratio, e.g., an aspect ratio between about ofabout 5:1 and about 20:1. As used herein, the aspect ratio is the ratioof a depth of the feature to a width of the feature. In embodiments, theone or more features 351 has a width 309 less than or equal to 20nanometers, less than or equal to 10 nanometers, or a width 309 between5 to 10 nanometers.

Still referring to FIG. 2, in some embodiments, method 200 may begin at202 by forming a remote plasma reaction between titanium tetrachloride(TiCl₄), hydrogen (H₂) and argon (Ar) in a region between a lid heaterand a showerhead of a process chamber at a first temperature of 200 to800 degrees Celsius. In some embodiments, method 200 continues at 204 byflowing reaction products such as reaction products from the remoteplasma reaction, into the process chamber to selectively form a titaniummaterial layer upon the silicon surface of the substrate. In someembodiments, the method includes forming a remote plasma reactionbetween titanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar)within a process chamber (such as process chamber 100 in FIG. 1) in aregion between a lid heater (such as lid heater 131 in FIG. 1) and ashowerhead (such as showerhead 165 shown in FIG. 1) to form reactionproducts suitable to form a titanium material layer 350 upon a substratesuch as semiconductor substrate 190 inside the process chamber toselectively deposit the titanium material layer 350 atop the siliconsurface 302 of the substrate. In embodiments, the dielectric surface 304inhibits deposition of the titanium material layer 350 atop thedielectric surface 304. In embodiments, a remote plasma reaction reactstitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) at a firsttemperature of 200 to 800 degrees Celsius. In some embodiments, thesubstrate such as semiconductor substrate 190 comprises a feature suchas a high aspect ratio feature, wherein the silicon surface 302 isdisposed at a bottom 307 of the high aspect ratio feature and thedielectric surface 304 is disposed on one or more sidewalls 314 of thehigh aspect ratio feature such as one or more features 351. In someembodiments, a first temperature is about 550 degrees Celsius, or below500 degrees Celsius. In some embodiments, about 65 watts of RF energy isapplied to the remote plasma reaction. In embodiments, the titaniummaterial layer is deposited to a predetermined thickness such as about10 angstroms to about 100 angstroms, or about 100 to about 500angstroms. In some embodiments, the titanium material layer 350comprises titanium, titanium silicide, or substantially pure titanium.

In some embodiment, method 200 further comprises adding silane compoundsuch as silane, hydrogen, and argon to the showerhead (such asshowerhead 165 in FIG. 1) to contact a remote plasma reaction. Inembodiments the titanium material layer 350 comprises or consists oftitanium silicide. In some embodiments, the titanium silicide ischaracterized as TiSix, wherein x is a number in the range of 0.4 to2.2.

Referring to FIG. 2, at process sequence 205, some embodiments of method200 may optionally include a post-deposition treatment of the titaniummaterial layer to further enhance selectivity and facilitate the robustformation of a semiconductor device. Accordingly, post-treating thetitanium material layer is included in the present disclosure. In someembodiments, post-treating the titanium material layer after depositionwill include preselected process sequences dependent upon the makeup ofthe deposited titanium material layer, e.g. whether the titaniummaterial layer is a result of remote plasma chemical vapor (CVD)deposition of titanium or remote plasma CVD deposition of titaniumsilicide.

The inventors have observed benefits of post-treating the titaniummaterial layer subsequent to deposition thereof. For example, theinventors have observed that residuals or reaction byproducts such astitanium chloride (TiClx or TiClx, wherein x is a number in the range of1 to 3, or wherein x=3) on the showerhead contributes to the formationof titanium nitride (TiN) and problematically deposits a TiN film atopboth the silicon surface or exposed silicon surface and the dielectricsurface such as a silicon nitride dielectric surface which degradesselectivity. The inventors have found that post-treatment after remoteplasma CVD titanium or remote plasma CVD titanium silicide is depositedand before any downstream nitridation passivates byproducts such astitanium chloride deposited or sticking to the showerhead and reduces aproblematic memory effect to below three angstroms.

In some embodiments, a post-deposition treatment is optionally performedsubsequent to remote plasma CVD deposition of titanium. The inventorshave observed that where a remote plasma reaction reacts titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) provided throughfirst gas flow line 162 and argon (Ar) provided through the second gasflow line 163 at a first temperature of 200 to 800 degrees Celsius,titanium chloride (TiClx) and hydrogen radicals may collect between theshowerhead and the substrate problematically resulting in titaniumchloride (TiClx) sticking to the showerhead surface and/or substrate topsurface. Subsequent to the formation of titanium chloride (TiClx), thetitanium chloride (TiClx) may be contacted with silane provided throughsecond gas flow line 163 which covers the titanium chloride (TiClx) andforms titanium silicide (TiSix) on the showerhead at a temperaturegreater than 400 degrees Celsius, such as 450 to 500 degrees Celsius, orbetween a temperature of 200 to 800 degrees Celsius. In someembodiments, the showerhead is at a temperature of 200 to 800 degreesCelsius, or about 500 degrees Celsius heated by radiation energy fromthe lid heater at a temperature of 200 to 800 degrees Celsius or about550 degrees Celsius. In embodiments, 0.5 liters to 3 liters of silanecompound such as silane is added. In embodiments, silane compound orsilane flows through second gas flow line 163 at 500 to 3000 sccm. Insome post-treatment embodiments, subsequent to the formation of titaniumsilicide (TiSix), silane compound or silane is purged from the processchamber by performing hydrogen soak and/or remote plasma soak wherehydrogen radicals react with the titanium silicide (TiSix) to form arobust titanium silicide (TiSix) composition that does not flake off theshowerhead and/or onto the substrate. In embodiments, titanium silicide(TiSix) has excellent adhesion and strong binding compared to titaniumchloride (TiClx). In some embodiments, the remote plasma is performed byflowing hydrogen and argon through the first gas flow line 162 whileflowing argon through the second gas flow line 163. In embodiments, theprocess chamber is grounded such that a remote plasma forms between thelid heater and showerhead. In some embodiments, subsequent to flowingreaction products into the process chamber to selectively form atitanium material layer upon the silicon surface of the substrate: thetitanium material layer is post-treated at a temperature greater than200 degrees Celsius or to a temperature of 200 to 800 degrees Celsius.In some embodiments, wherein the titanium material layer comprises orconsists of titanium the post-treating or post-treatment includescontacting the titanium with silane and one or more of hydrogen orhydrogen radicals.

In some embodiments, a post-deposition treatment is optionally performedsubsequent to remote plasma CVD deposition of titanium silicide. Theinventors have observed that where a remote plasma reaction reactstitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) providedthrough first gas flow line 162 and argon (Ar) and silane providedthrough the second gas flow line 163 at a first temperature of 200 to800 degrees Celsius, titanium chloride (TiClx), hydrogen radicals andsilane compound such as silane react between the showerhead and thesubstrate to form titanium silicide (TiSix) on the showerhead surfaceand/or substrate top surface. The inclusion of silane compound such assilane in the deposition reactants forms problematic titanium silicide(TiSix). Subsequent to the formation of titanium silicide (TiSix),silane is purged from the process chamber by performing hydrogen soakand/or remote plasma soak where hydrogen radicals react with thetitanium silicide (TiSix) to form a robust titanium silicide (TiSix)composition that does not flake onto the substrate or off theshowerhead. In embodiments, titanium silicide (TiSix) has excellentadhesion and strong binding. In some remote plasma CVD deposition oftitanium silicide embodiments, a silane soak process sequence is notperformed as, in embodiments, the deposition chemistry includes silane.In some embodiments, the remote plasma is performed by flowing hydrogenand argon through the first gas flow line 162 while flowing argonthrough the second gas flow line 163. In embodiments, the processchamber is grounded such that a remote plasma forms between the heaterlid and showerhead. In some embodiments, the titanium material layer tobe post-treated comprises or consists of titanium silicide and thepost-treating comprises contacting the titanium silicide with one ormore of hydrogen or hydrogen radicals such as in an amount sufficient tomake the titanium silicide robust.

In some embodiments, method 200 may further include forming a directplasma reaction between nitrogen (N₂), hydrogen (H₂) and argon (Ar)inside a process chamber (such as process chamber 100 in FIG. 1) betweenthe showerhead (such as showerhead 165 in FIG. 1) and the substrate toform a titanium nitride capping layer 370 upon or within the titaniummaterial layer 350 atop the silicon surface 302 of the semiconductorsubstrate 190. In some embodiments, a direct plasma nitrogen andhydrogen reaction is provided to form titanium nitride capping layer370. In some embodiments, the direct plasma reaction is performedsubsequent to post-treating the titanium material layer 350 as describedabove. In some embodiments nitrogen is included in the direct plasmareaction in an amount of 4 to 8 standard liters per minute (slpm) orabout 6 slpm. In some embodiments, hydrogen is provided to the directplasma reaction in an amount of 0.5 to 2 slpm, or about 1 slpm. Inembodiments argon is provided the direct plasma reaction in an amount of2 to 5 slpm such as 3.75 slpm. In embodiments, the process chamberduring the direct plasma reaction has a pressure of about 1 to 8 Torr,such as 4 Torr. In embodiments, RF power is applied during the directplasma reaction at about 500 watts. In some embodiments the wafertemperature is maintained during the direct plasma reaction at atemperature of 200 to 800 degrees Celsius such as about 425 degreesCelsius. In some embodiments, the lid heater is heated during the directplasma reaction to a temperature of 200 to 800 degrees Celsius such asabout 550 degrees Celsius. In some embodiments a pedestal temperatureduring the direct plasma reaction is maintained at a temperature of 200to 800 degrees Celsius, or about 450 degrees Celsius.

In some embodiments, the nitridation process sequence or the directplasma reaction provides nitrogen at a flow rate of about 0.1 slpm to 6slpm, and hydrogen in an amount of 0.1 slpm to 6 slpm. In embodiments,the pressure of the process chamber during the direct plasma reaction ismaintained at 1 Torr to 15 Torr. In embodiments, RF power is appliedduring the direct plasma reaction at about 100 watts to 1000 watts.

FIG. 4 is a flowchart of a method 400 of selective deposition inaccordance with some embodiments of the present disclosure. FIGS. 5A-5Care illustrative cross-sectional views of the substrate during differentstages of the processing sequence of FIG. 4 in accordance with someembodiments of the present disclosure. The methods of the presentdisclosure may be performed in process chambers configured for thermaldeposition techniques such as chemical vapor deposition (CVD), or theprocess chamber discussed above with respect to FIG. 1.

In embodiments, the method 400 is performed on a semiconductor substrate590, as depicted in FIG. 5A, having a silicon surface 502 and one ormore dielectric surfaces such as dielectric surface 504. In embodiments,semiconductor substrate 590 may comprise a silicon material 501 such assilicon material 301 described above.

In some embodiments, silicon material 501 is deposited via any suitableatomic layer deposition process or a chemical layer deposition process.In some embodiments, the silicon material 501 may comprise any suitablesilicon material for semiconductor device fabrication. Referring to FIG.5A, a silicon oxide layer (not shown) may be atop silicon surface 502.The silicon oxide layer may be a native oxide layer 510 (shown inphantom in FIG. 5A) or form as silicon surface 502 contacts oxygen, forexample in air or water. In some embodiments, silicon oxide layer may beproblematic in that the silicon oxide layer may be less selectivetowards titanium materials than an exposed silicon surface. In someembodiments, method 400 may include, pre-treating the silicon surface502 to form an exposed silicon surface. In some embodiments, methodsinclude contacting the silicon surface 502 with one or more etchants toform an exposed silicon surface 502. In some embodiments, a siliconoxide layer is removed prior to depositing a titanium material atop, ordirectly atop silicon surface 502 to form an exposed silicon surface.Non-limiting examples of exposed silicon surface material includessubstantially pure, for example, substantially free of oxide, siliconand the like. In some embodiments, the semiconductor substrate 590 maybe pretreated and post-treated as described above. In some embodiments,a post-deposition treatment is optionally performed subsequent to remoteplasma CVD deposition of titanium silicide as described above. In someembodiments, a post-deposition treatment is optionally performedsubsequent to remote plasma CVD deposition of titanium as describedabove.

In embodiments, dielectric layer 505 including dielectric surface 504 isnot the same as silicon material 501 including silicon surface 502. Insome embodiments, the dielectric layer 505 is deposited via any suitableatomic layer deposition process or a chemical layer deposition process.In embodiments, dielectric layer 505 and dielectric surface 504 compriseor consist of silicon oxide (SiO2), silicon nitride, silicon oxynitride(SiON), or combinations thereof.

In embodiments, the dielectric layer 505 may include one or morefeatures 551 such as a via or trench formed in the dielectric layer 505.The one or more features 551 may be formed by etching the dielectriclayer 505 using any suitable etch process. In some embodiments, the oneor more features 551 is defined by one or more sidewalls 514, an opening522 and upper corners 521. In some embodiments, the one or more features551 may have a high aspect ratio, e.g., an aspect ratio between about ofabout 5:1 and about 20:1. As used herein, the aspect ratio is the ratioof a depth of the feature to a width of the feature. In embodiments, theone or more features 551 has a width 509 less than or equal to 20nanometers, less than or equal to 10 nanometers, or a width 509 between5 to 10 nanometers.

In embodiments, method 400 begins at 402 (shown in phantom) byoptionally, forming a first direct plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) inside a processchamber in a region between a showerhead and a substrate for a durationof 0.1 to 200 seconds. In embodiments, a layer such as monolayer oftitanium material 511 (shown in FIG. 5B) may be deposited upon thesilicon surface 502 to prime the silicon surface 502 for furtherdeposition. In embodiments, the first direct plasma reaction isperformed for a very short duration such as 0.1 to 200 seconds. Inembodiments, the first direct plasma reaction is performed at atemperature of 200 to 800 degrees Celsius, or 300 to 700 degreesCelsius. In embodiments, titanium tetrachloride (TiCl₄), hydrogen (H₂)and argon (Ar) are provided to a process chamber in an amount sufficientto prime the silicon surface 502 for further deposition. In embodiments,titanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) areprovided to a process chamber in an amount sufficient to deposit amonolayer of titanium material 511 such as titanium upon the siliconsurface 502.

In embodiments, method 400 may begin at process sequence 404 by forminga remote plasma reaction between titanium tetrachloride (TiCl₄),hydrogen (H₂) and argon (Ar) within a process chamber such as in aregion between a lid heater and a showerhead to form a titanium materiallayer 550 (shown in FIG. 5B) upon a semiconductor substrate 590 inside aprocessing chamber to selectively deposit the titanium material layer550 atop the silicon surface 502 of the semiconductor substrate 590,wherein the dielectric surface 504 inhibits deposition of the titaniummaterial layer 550 atop the dielectric surface 504. In embodiments, theremote plasma reaction reacts titanium tetrachloride (TiCl₄), hydrogen(H₂) and argon (Ar) at a first temperature of 200 to 800 degreesCelsius.

In some embodiments the remote plasma reaction may form a titaniumsilicide as titanium material layer 550. For example, in embodiments,forming a remote plasma reaction between titanium tetrachloride (TiCl₄),hydrogen (H₂) and argon (Ar) within a process chamber between a lidheater and a showerhead further comprises adding silane, hydrogen, andargon to the showerhead to contact the remote plasma reaction. In someembodiments, the silane, hydrogen, and argon may be supplied via secondflow line 163 as shown in FIG. 1.

In some embodiments, the method 400 may optionally include post-treatingthe titanium material layer atop the substrate as shown in method 400 atprocess sequence 405. In embodiments, the post-treating includesembodiments, described above with respect to method 200 at processsequence 205.

In embodiments, method 400 includes at 406 (as shown in FIG. 5C) forminga direct plasma reaction between nitrogen (N₂), hydrogen (H₂) and argon(Ar) inside a process chamber in a region between the showerhead and thesubstrate to form a titanium nitride layer 559 upon the titaniummaterial layer 550 atop or within the silicon surface 502 of thesubstrate. In some embodiments, the titanium nitride layer 559 formswithin the titanium material layer 550.

In embodiments, as shown in FIG. 5C, the silicon surface 502 is at abottom of a feature 551. In embodiments, methods of the presentdisclosure further comprise filling the feature from a bottom to a top525 with metal fill 523 such as cobalt or tungsten.

In embodiments, the present disclosure relates to a processing chamber,comprising: a lid heater; a showerhead; and a substrate supportpositioned within the processing chamber, wherein the processing chamberis configured to remotely ignite a plasma in a region between the lidheater and the showerhead and directly ignite a plasma in a regionbetween the showerhead and the substrate support. In some embodiments,the lid heater comprises an RF electrode for emitting RF energy into theprocessing chamber. In some embodiments, the showerhead comprises an RFelectrode for emitting RF energy into the processing chamber. In someembodiments, the showerhead may optionally be connected to a ground. Forexample, depending on the user needs and desired placement of plasma inthe processing chamber, the showerhead may be grounded, or ungrounded.In embodiments, the showerhead is connected to a ground to remotelyignite a plasma inside a process chamber between a lid heater and ashowerhead. In some embodiments, the showerhead is not connected to aground to directly ignite a plasma inside a process chamber between theshowerhead and the substrate. In embodiments, the substrate support isconnected to a ground. In some embodiments, the process chamber includesa switch 184 in communication with the ground 183 and RF electrode 180and configured to control remote and direct plasma formation inaccordance with the present disclosure and depending upon user needs. Inembodiments the switch 184 and showerhead 165 are in communication andconfigured to control remote and direct plasma formation in accordancewith the present disclosure and depending upon user needs. In someembodiments, about 65 watts to 150 watts of RF energy is applied to theremote plasma reaction within process volume 101. In some embodiments,RF energy is about 120 watts to 140 watts or 130 about watts to theremote plasma reaction within process volume 101. In some embodiments,pulsed RF energy or RF in a continuous wave mode is applied to theremote plasma reaction within process volume 101. In some embodiments,the RF power is about 130 watts, with a pulsed frequency of about 1 kHz,with duty cycle about 50% in the remote plasma reaction within processvolume 101.

In some embodiments, the present disclosure relates to a method ofselectively depositing a titanium material layer atop a substrate havinga silicon surface and a dielectric surface, including: forming a remoteplasma reaction between titanium tetrachloride (TiCl₄), hydrogen (H₂)and a noble gas such as argon (Ar) in a region between a lid heater anda showerhead of a process chamber at a first temperature of 200 to 800degrees Celsius to form one or more reaction products; and flowing theone or more reaction products into the process chamber to selectivelyform a titanium material layer upon the silicon surface of thesubstrate. In some embodiments, the methods include adding one or moresilane compounds, hydrogen, and a noble gas such as argon to theshowerhead to contact the remote plasma reaction. In some embodiments,the one or more silane compounds include one or more of silane (SiH₄),disilane (Si₂H₆), trisilane (Si₃H₈), and tetrasilane (Si₄H₁₀), orcombinations thereof. In embodiments, one or more silane compounds areadded in an amount sufficient to form TiSix in accordance with thepresent disclosure.

The disclosure may be practiced using other semiconductor substrateprocessing systems wherein the processing parameters may be adjusted toachieve acceptable characteristics by those skilled in the art byutilizing the teachings disclosed herein without departing from thespirit of the disclosure.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof.

The invention claimed is:
 1. A method of selectively depositing atitanium material layer atop a substrate having a silicon surface and adielectric surface, comprising: forming a remote plasma reaction betweentitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) in a regionbetween a lid heater and a showerhead of a process chamber at a firsttemperature of 200 to 800 degrees Celsius; and flowing reaction productsinto the process chamber to selectively form a titanium material layerupon the silicon surface of the substrate.
 2. The method of claim 1,wherein the substrate comprises a high aspect ratio feature, wherein thesilicon surface is disposed at a bottom of the high aspect ratio featureand the dielectric surface is disposed on one or more sidewalls of thehigh aspect ratio feature.
 3. The method of claim 1, wherein the firsttemperature is about 550 degrees Celsius.
 4. The method of claim 1,wherein about 65 watts of RF energy is applied to the remote plasmareaction.
 5. The method of claim 1, wherein the titanium material layeris deposited to a predetermined thickness.
 6. The method of claim 1,wherein the titanium material layer comprises titanium, titaniumsilicide or substantially pure titanium.
 7. The method of claim 1,further comprising adding silane, disilane, hydrogen, and argon to theshowerhead to contact the remote plasma reaction.
 8. The method of claim7, wherein the titanium material layer comprises titanium silicide. 9.The method of claim 1, further comprises forming a direct plasmareaction between nitrogen (N₂), hydrogen (H₂) and argon (Ar) atemperature of 200 to 800 degrees Celsius inside a process chamberbetween the showerhead and the substrate to form a titanium nitridecapping layer upon the titanium material layer atop the silicon surfaceof the substrate.
 10. The method of claim 1, wherein the dielectricsurface comprises silicon oxide or silicon nitride.
 11. The method ofclaim 1, further comprising prior to selectively forming a titaniummaterial layer upon the silicon surface of the substrate: preheating thesubstrate to a temperature of 200 to 800 degrees Celsius and contactingthe substrate and dielectric surface with argon, hydrogen, silane, andcombinations thereof.
 12. The method of claim 1, further comprisingsubsequent to flowing reaction products into the process chamber toselectively form a titanium material layer upon the silicon surface ofthe substrate: post-treating the titanium material layer at atemperature greater than 200 degrees Celsius.
 13. The method of claim12, wherein the titanium material layer comprises or consists oftitanium and post-treating further comprises contacting the titaniumwith silane and one or more of hydrogen or hydrogen radicals.
 14. Themethod of claim 12, wherein the titanium material layer comprises orconsists of titanium silicide and the post-treating comprises contactingthe titanium silicide with one or more of hydrogen or hydrogen radicals.15. A method of depositing a titanium material layer atop a substratehaving a silicon surface and a dielectric surface, comprising:optionally, forming a first direct plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) inside a processchamber between a showerhead and the substrate for a duration of 0.1 to200 seconds to deposit a layer of titanium material on the siliconsurface of the substrate; forming a remote plasma reaction betweentitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) within theprocess chamber between a lid heater and a showerhead of a processchamber to form a titanium material layer upon the substrate inside theprocessing chamber to selectively deposit the titanium material layeratop the silicon surface of the substrate or the optionally formed layerof titanium material on the silicon surface, wherein the dielectricsurface inhibits deposition of the titanium material layer atop thedielectric surface, and wherein the remote plasma reaction reactstitanium tetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) at a firsttemperature of 200 to 800 degrees Celsius; and subsequently forming adirect plasma reaction between nitrogen (N₂), hydrogen (H₂) and argon(Ar) inside the process chamber between the showerhead and the substrateto form a titanium nitride layer upon the titanium material layer atopthe silicon surface of the substrate.
 16. The method of claim 15,wherein forming the remote plasma reaction between titaniumtetrachloride (TiCl₄), hydrogen (H₂) and argon (Ar) within a processchamber between the lid heater and the showerhead further comprisesadding silane, hydrogen, and argon to the showerhead to contact theremote plasma reaction.
 17. The method of claim 15, wherein the siliconsurface is at a bottom of a feature, and wherein the method furthercomprises filling the feature atop the titanium nitride layer from thebottom to a top of the feature with cobalt or tungsten.
 18. The methodof claim 15, further comprising prior to subsequently forming the directplasma: post-treating the titanium material layer at a temperaturegreater than 200 degrees Celsius.